Durendal is an immensely powerful Sword of Power that is linked to elemental air magic. The weapon, carved out of stone, is well-polished, dull-grey, and about three feet in length. Despite the material generally being vulnerable to weathering and shattering, the weapon is effectively impossible to destroy. In contrast to Excalibur and Clarent, which feature in numerous legends and play prominent roles throughout the series, little is known about Durendal and its history. Dee uses the four swords to create a ley gate to Coatlicue's Shadowrealm in an attempt to free the Archon, and along with the other swords Durendal becomes a part of Marethyu'sHook of Aether.

Powers

Corruption: Prolonged use of the swords can damage the mind of the wielder. Mars Ultor, Mordred, and Cernunnos were corrupted and nearly destroyed by the swords.

Telepathic Linking: Wounding or killing something with one of the swords of power will allow partial access to the memories and experiences of whatever the sword was connected with.

Killing: Like the other swords of power, Durendal can kill almost anything. Some things (such as Coatlicue) may be immune to its power, however Clarent was capable of killing the Nidhogg.

Creation of Ley Lines: Together the swords of power are capable of creating ley lines and ley gates. For instance, Dr. John Dee created a portal into Coatlicue's Shadowrealm using the four swords together.

Trivia

In the Matter of France, Durendal is the sword of Roland, paladin of Charlemagne. According to local folklore, the sword is embedded in the cliff at Rocamadour in France, though the officials in the area call it a replica.